The present invention relates generally to hood shield units for the front areas of road vehicles such as light duty trucks, pickup trucks, and vans, as well as automobiles and the like.
Most automotive vehicles offered for sale today, particularly ordinary automobiles and light trucks of various kinds, including pickup trucks and vans, have, when considered in their front aspect, certain surfaces which are generally resistant to damage from airborne objects such as particles of gravel, sand, flying insects, debris falling from other road vehicles, and the like. The portions of most modern vehicles lying beneath the bumper are usually made from plastic or coated metal which is relatively impact resistant, and which, not being readily visible in most cases, is not normally finished with high gloss materials. Above this area is the vehicle bumper, which is commonly made from metal and covered with either rubber or rubber-coated material, or from an impact resistant, bright-finished material such as chrome plated steel, anodized aluminum or the like.
Above the bumper level are other materials which include an impact-resistant finish. These include headlights, headlight covers and their associated moldings, vehicle grillework and the like. These elements are often made from an impact-resistant molded plastic, from chrome plated metal, or from anodized aluminum or the like. Those portions of the frontal aspect of the vehicle that do not possess a bright finish are often made from other impact-resistant materials, such as plastic or metal with a matte black finish or the like. All of these areas resist impact damage from sand, gravel, etc., or at least do not readily show damage if it is present.
In most cases, the glossy painted finish of the vehicle begins at and extends upwardly from the front of the hood line, i.e., the area where the lower front part of the hood joins the remainder of the vehicle. The portions of the vehicle extending rearwardly from the grille, over and/or around the fenders and elsewhere on the vehicle, are usually painted with a high gloss finish. In other words, the portions of the vehicle, such as the bumper, lights and grille are generally made from impact resistant materials below the hood line, while the vehicle parts above the hood line are provided with a glossy finish.
Where portions of the vehicle front extend vertically or lie at or slightly behind the plane of the forwardmost section of the vehicle, there is significant exposure in use of the vehicle to sand, gravel, and other airborne particles which, with the passage of time, disfigure or even damage the vehicle front end. In particular, the front of the hood and other areas is susceptible to impact damage from sand, gravel and the like.
This problem is not as pressing in certain urban areas, which have well maintained roads, as it is in rural areas, but gravel damage and the like can be a significant problem with vehicles which traverse sand or gravel roads, or even hard surface roads which occassionally have deposits of sand, gravel or the like on them. In addition, many areas of the country, particularly dessert and agricultural areas, have an everyday atmosphere in which significant amounts of sand, gravel or other abrasives are simply entrained in the air as a result of the wind movement.
In order to forestall damage to the lower forward portion of the hoods on such vehicles, and the upper portion or entire hood area on certain vehicles such as vans or the like, it has been common to provide hood shields or deflectors for protection of the vehicle finish in this area. Customarily, these are contoured units roughly paralleling the front surface of the lower part of the hood and extending first upwardly and then rearwardly in this area. In the past, such units have often been made from plastic sheet materials for reasons of manufacturing ease, low cost and ready formability.
The most popular materials for this purpose have been the acrylic plastic materials, polycarbonate ("Lexan") plastics and in some cases, modified acrylics or modified cellulose acetate materials, such as "CAB" or the like. Many, if not all prior art hood shield of this type, because of their contours, possess significant stress concentrations or stress "risers" which create risks of cracking or breakage. Usually, these areas are found in the transition surfaces between the impact receiving or most vertical portion of the shield and the mounting flange, and/or at and around the areas wherein the shield mounting fasteners are positioned.
In cases where the shield is rigidly mounted along a rear edge or margin, and no means are provided to prevent cracking, applying undue force to the body of the shield will often cause cracking or breakage either along the sharply curved or contoured regions. A more common type of failure occurs adjacent the rearward sections of the shield mounting flange. Here, where mounting tabs have been provided, and fasteners have been used to secure these areas to the vehicle hood, stress concentrations are great, and with continued vibration and other stresses, the underlying material becomes embrittled and stress concentrations lead to cracks or other premature failure.
In other cases, where mounting tabs are not provided, the shield may also be subjected to breakage around the fastener openings. These stresses can result from abrasion or fastener overtightening, for example. Leaving fasteners loose can create wear and distortion of the openings, while excess tightening amplifies vibration.
In those cases wherein the mounting flange of the shield has been designed to pass beneath the lowermost flange of the hood, prior art designs have often used narrow thicknesses of material or sharply angled formations to fit in the limited space available. This has acted to create other instances of high stress concentrations leading to premature failure. As is implicit from the foregoing statements, as the space between opposed facing surfaces of the vehicle body forming the hood parting line is reduced, the problem of providing space for the passage of the deflector or its mounting system become more difficult. Consequently, maladjustment of the hood clearance can cause the hood to strike and pinch the deflector shield when the hood is not carefully closed. In some cases, the shield may inadvertently be permanently clamped between opposed facing surfaces of the hood flange and the hood locking or positioning units adjacent the engine bay of the vehicle.
In view of the foregoing shortcomings of prior art hood shields, there has been a need for a deflector shield which may be readily installed on vehicles in spite of very close or minimal clearances between adjacent relatively fixed and movable hood-locking portions of an automobile.
In addition, there has been a demand for a mounting system which, under ordinarily foreseeable conditions, will not subject the elements of the shield assembly to breakage in use. In particular, there has been a demand for a mounting system whereby, if there is a breakage or failure of an installed shield unit, the breakage is not that of the major, most expensive part of the assembly. In addition to the need for overcoming the foregoing problems, there has also been a need for shield designs which are more convenient in installation and use and which may be made without sacrifice of advantageous features or incorporating other disadvantages. A desirable shield includes additional features such as multi-vehicle adaptability, adaptability to providing bug deflectors and the like.
In view of the failure of the prior art to overcome the foregoing difficulties, it is an object of the present invention to provide an improved hood shield assembly for motor vehicles.
Another object of the present invention is to provide an improved hood shield assembly which includes a one-piece contoured deflector unit with a principal or impact-resisting section and a mounting section, with a plurality of mounting brackets secured to the vehicle along one locus and secured to the shield by breakaway fasteners extending between selected portions of the shield and parts of the mounting brackets forming a part of the assembly.
A still further object of the invention is to provide a hood shield assembly having a deflector unit which includes a mounting section joined to a contoured principal section by a transition section which is free from excess stress concentrations.
A further object is to provide a shield assembly arranged so as to be adaptable for use with a variety of bracket units, each individually tailored to a particular application, whereby various models of similar vehicles may use the same or similar deflector screen and different brackets without sacrificing the breakaway mounting feature of the invention.
The foregoing and other objects of the invention are achieved in practice by providing a shield assembly for attachment to the hood of the road vehicle wherein the shield assembly includes a one-piece deflector unit with a principal section adapted to protect the exterior surface of the vehicle hood and a rearwardly extending mounting section, a plurality of mounting brackets, each including hood attachment and shield attachment sections, with the mounting brackets being secured to the shield by frangible fasteners having an ultimate yield strength such that forces tending to separate the deflector unit from the brackets will cause the fasteners to break before the elastic limits of the deflector unit are reached or exceeded. Preferably, the mounting brackets are of metal and have a thinner cross-section than the material from which the shield is made.